There is a lot of uncertainty when it comes to iron-rich foods. Which foods ('Apart from spinach, it contains a lot of iron, doesn't it?') contain how much iron, how much of it we need and what it's actually there for, these are all questions that arise.
In this article you will find out how much iron you should actually be consuming. Also, if there's a good chance you already do. And, if this is not the case, what options you have to prevent a deficiency and how you can recognize it.
the essentials in brief
- Iron is a vital trace element. It serves to ensure that your body is sufficiently supplied with oxygen. If you don't take in enough iron, your body falls back on stored iron.
- The need for iron varies from person to person. For example, it is increased during menstruation or pregnancy, but also after a blood donation.
- Iron deficiency can occur for a variety of reasons. The stronger he is, the more severe his symptoms become. However, the deficiency can be treated well, for example with iron tablets.
Iron-rich foods: what you should know
Most people know that we have iron in our bodies. Many are familiar with the expression 'it tastes of iron' when you taste blood. But very few people know how iron gets into our blood, what it is doing there and how much there should be.
That should change by the time you read this article. We have put together the answers to the most important questions about iron in your body.
Why do I need iron in my body?
Iron in your body is mainly necessary for the transport of oxygen. The oxygen is bound to the iron and transported through the body in the blood. Since this is a vital task, your body has always stored iron in various organs to prevent a deficiency from occurring. However, to prevent this from happening, you need to get enough iron, as only a small portion of it is actually absorbed into the body (2).
Iron is important for the transport of oxygen, without it we could not supply our body. (Image source: Pixabay / Free-Photos)
Especially when people are pregnant or menstruating, iron deficiencies or even anemia can occur. This is due to the increased need for iron due to the child’s blood formation and blood loss. These groups of people should therefore pay even more attention to ensuring that there is enough of the trace element in the body (3,4,5">.
How Much Iron Should I Consume?
How much iron you should consume depends on various factors. For example, it matters what source it comes from, how well it is absorbed, and what the need is. Since only part of the iron can be absorbed from food or supplements, a larger amount has to be consumed than the body needs. The unused iron is then simply excreted, unless the amounts involved are extremely large.
| life stage | Recommended daily iron intake |
|---|---|
| infant | 8mg |
| Toddler (1-7) | 8mg |
| child (10-15) | 12-15 mg |
| teenagers | 12-15 mg |
| pregnancy | 30 mg |
| lactation | 20 mg |
| Adult | 10-15 mg |
(1,2,7,8,9)
However, as mentioned earlier, iron needs vary from person to person. The values mentioned should therefore only serve as guide values.
An important factor in iron absorption is its absorption. It comes in two different forms: heme iron, also called animal iron, and non-heme iron found in plant foods. The former is much more bioavailable, so easier for the body to absorb (2,5,10">.
Another factor are the substances that inhibit or promote the absorption of iron. Some of these are summarized in the table below:
| Substances that promote iron absorption | Substances that inhibit iron absorption |
|---|---|
| Vitamin C (in fruits, vegetables) | Calcium (in milk, cheese) |
| lactic acid, citric acid | phytic acid (in grain products) |
| Vitamin A | Phenolic compounds (in coffee, red wine) |
(1,5,10)
The iron intake is therefore complex and not easy for laypeople to understand. That's why checking your iron level from time to time is a sensible thing to do.
What foods contain iron?
Iron is found in many different foods, which is why the need is usually covered by itself. However, the amount is different. It can be useful, especially for people who do not eat certain foods, to get an overview of the iron content of others.
| Groceries | Iron content (per 100 g) |
|---|---|
| oatmeal | 4.4 mg |
| Boiled Lentils | 3.1 mg |
| tofu | 2.8 mg |
| sesame butter | 8.8 mg |
| arugula | 1.5 mg |
| lettuce | 30 mg |
| spinach | 40 mg |
| muscle meat | 5 mg |
| liver | 20-30mg |
(7.8)
How well the iron is absorbed varies from food to food. This is also related to substances that can inhibit or promote absorption.
How does an iron deficiency manifest itself?
Even a mild iron deficiency can cause many symptoms. If there is a severe shortage, these become even more severe. Some of them are the following:
- fatigue
- lack of concentration
- Decreased performance
- depressed mood
- weakened immune system
- Brittle nails
- hair loss
(2.5)
Since all of these symptoms do not necessarily point unequivocally and exclusively to an iron deficiency, it is advisable to consult a doctor before taking steps to counteract a deficiency.
While iron deficiency is common, medical advice should be sought before supplements are used.
What should I pay attention to if I eat vegetarian or vegan?
Because heme iron is not consumed on an all-vegetable or mostly plant-based diet, it is more difficult for the body to absorb it. Then it can make sense to take a closer look at the inhibiting and promoting substances for iron absorption, which we reported on above. In one of the tables we have also already collected some plant foods for you with their iron content.
Vegetables contain only non-heme iron, which is harder for the body to absorb. However, absorption increases when heme iron is no longer supplied. (Image Source: Unsplash / Ja Ma)
However, it can make sense to take iron supplements, especially for people with an increased need for iron. However, this should only happen with the doctor's agreement. A deficiency does not have to arise just because no animal iron is consumed. In fact, there appears to be a dedicated plant-based iron pathway that works independently of heme and non-heme iron (2.10">.
It is not necessary to consume animal products to meet iron requirements.
Which iron-rich foods are suitable for my dog?
In principle, iron absorption in dogs is the same as in humans. However, the amount of iron required is of course different. And, also like humans, it depends on how well the iron is absorbed.
Since dry food or bloodless meat is not necessarily a sufficient source of iron for a dog, care should be taken to take a supplement if necessary. However, this is not necessary if the food resembles prey: the daily requirement is quickly covered with meat, bones and vegetables that have not been bled to death (6).
What alternatives are there to iron-rich foods?
Certain diets or a high iron requirement can mean that your body cannot absorb enough iron from food. But there is a remedy, which we will present to you in the following paragraph.
iron supplements
If you're not getting enough iron from your diet because you're eating too little or foods that are low in iron, you can still prevent a deficiency. There are iron supplements for oral intake or intravenous iron therapy.
Although iron deficiency is one of the most common deficiencies worldwide, current studies on therapy are rare. However, it is already known from older studies that iron in tablet form is well suited if it involves soluble iron(II) compounds. Iron(III) compounds, on the other hand, are less easily absorbed because they are less soluble. Intravenous iron therapy is still not very common, but is used, for example, to treat chronic hemodialysis or chronic inflammatory bowel disease (5).
However, side effects can also occur when using supplements. In the case of oral therapy, this includes, for example, nausea, diarrhea or constipation. However, this can be counteracted by taking the right dosage and timing.
Conclusion
Although many foods contain iron, it is difficult to know what to eat and how much to eat. The multitude of factors affecting not only demand but also absorption makes the subject even more obscure.
However, the factors described make it possible to draw attention to the issue of iron and increase the likelihood that problems will be identified quickly. It is quite possible to prevent iron deficiency with iron-rich foods, and if one does occur, it can be treated well with supplements.
References
- Rehberg, Carina (2020). Foods High in Iron – The foods richest in iron. Center of Health at: https://www.zentrum-der-gesundheit.de/artikel/healthy-eating/eisenreiche-lebensmittel
- Günther K. (2019) How much can it be? Iron requirement, deficiency and excess. In: Eliminating Iron Deficiency with Natural Foods. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-662-58342-5_4
- Laura Percy, Diana Mansour, Ian Fraser, Iron deficiency and iron deficiency anemia in women, Best Practice & Research Clinical Obstetrics & Gynaecology, Volume 40.
- Low MS, Speedy J, Styles CE, De-Regil LM, Pasricha SR. Daily iron supplementation for improving anemia, iron status and health in menstruating women. Cochrane Database Syst Rev. 2016 Apr 18;4:CD009747. doi: 10.1002/14651858.CD009747.pub2. PMID: 27087396.
- Nielsen P (2016) Iron. In: Singbartl G., Singbartl K. (eds) Transfusion-associated pharmacotherapy. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-662-47258-3_1
- Garbers, Frauke. Iron. On: species-appropriate. https://www.artrecht-tier.de/lexikon/naehrstoffe/d-eisen-1898523191
- Plank, R., Greber-Platzer, S., Haiden, N. et al. Safety and risks of vegetarian and vegan diets during pregnancy, breastfeeding and the first years of life. Monthly Schr Kinderheilkd 167, 22-35 (2019). https://doi.org/10.1007/s00112-018-0554-7
- The importance of trace elements in human nutrition Aebi, H. The importance of trace elements for human nutrition. Z. Preventive Med 1, 137-149 (1956). https://doi.org/10.1007/BF02031649
- Hähn, N., Paschen, K. & Haller, J. The behavior of copper, iron, magnesium, calcium and zinc in women with a normal menstrual cycle, taking ovulation inhibitors and during pregnancy. Arch. Gynak. 213, 176-186 (1972). https://doi.org/10.1007/BF00667673
- Ströhle, A., Waldmann, A., Wolters, M. et al. Vegetarian Diet: Preventive Potential and Possible Risks. Vienna Klin Wochenschr 118, 728-737 (2006). https://doi.org/10.1007/s00508-006-0716-9
